Telephone system



Dec. 26, 1922.

C. SPARKS TELEPHONE SYSTEM ORIGINAL FILED AUG. 5. 1918.

2 SHEETS-SHEET 1 or: fizgj jvarirs. 5

Patented Dec. 26, 1922.

U N lT- E-D S TA CHARLES scans on oak ANDSUPPLY comma,

1,440,114 PATENT orr ca.

ILIIINOIS, ASSIGNOR- TO KELLOGG SWITCHBOARD OF CHICAGO, ILLINOIS, A CORPORATION OF ILLHVOIS.

' 'j'rnnarnona. SYSTEM.

Annlication filed August 5, iaisf;se arate-8321. Renewed August 11, 1922. Serial no. 58mm To allwlwmz't may concenz Be it known that? GnaRLEsSPAnKs, a citizen'of't-heUnited bta t'es of America,- re-- siding in Oak Park,'('st' 'unty (if-(look, and State of Illinois, have invented certain n'ew and useful Improvements in Telephone fiysterns, ofuhich the following is a specification.

My invention relates to telephone systems and has to do more particularly with sys-j teins using linkor cord circuits for use inf interconnecting telephonilines offditferent'; character; such as'comiiion battery-ans 'local battery lines;

A feature 'of my invention is the provision of memswliereby whena batterysubscriber has terminated conversation theusual supervisory si a1 is lightedtonotify' the operator-that 'onneet1on""is' desired,

and whereby when a local battery'subscriber has terminated conversation the disconnect signal sent by the subscriber'operatesmeans to causethesupefvisory'signal' to' llash in-ftermittently, independently of the disconnect signal sent by thesubscriber. i

Another feature of my invention is the provision of means whereby'as long' as the subscriber is ringing in One localbattery line the flash disconnectappar'atus is reudered inoperative to flash the supervisory lamp.

These as well as other features will be more particularly pointed out in the ensuing specification and in the appended claims.

For a better understanding of my invention, reference may be had to the accompanying drawings which illustrate my invention operating in connection with a telephone system, and in which:

Fig. 1 illustrates one form of my Invention operating in connection with a univer-' sal cord circuit in which automatic ringin;' is provided; and

Fig. 2 illustrates my invention operating in connection with a universal cord circuit common battery and common battery lines,

or local battery and local battery lines. To the left of the drawing. T show a call ng common battery substation A and a calling exchange in line circuits L and L, with the usual line ielavs LR and LR-, cut ofl relays (Q0 and CO. line signals S and S, and multiple jacks J and J. The local battery substations B and E terminate respectively at the exchangein linecircuits L and L,

which line circuits comprise the hi h resistan'ce wound cut-01f relays-CO an CO,

- multiple jacks J and J and drop signals DS 'and DS.

The universal cord circuit C comprises an answering plu AP and a calling plug GP, the two plugs being connected by the heavily marked conductors and through the medium of a repeating coil'RP, comprisin windings 1. 2; 3 and 4. The answering end of the cord circuit C comprises a switching relay SW, which relay energizes when the plugAP is insertedinto the jack of a commonbattery line, the said relay SW remaining at normal when the plug 'AP is inserted intothe jack of a local battery line, due to the high resistance of the winding of the cut-off relay of the local battery line circuit. A supervisory relay SR- is provided which is actuated over the linewhcn a connection is made with a common battery line. A disconnect relay DR is also provided which is actuated when a local hatlcry subscriber transmits a disconnect signal to the exchange by the operation of his hand generator. An answering supervisory lamp AL is also associated with the answering end of the cord circuit C for the usual supervisory purposes. The calling end of the cord circuit G contains similar apparatus to that described in connection with the answering end of the cord circuit C. namely. a switching relay SW, a su )ervisory relay SR. and a disconnect relay R. In addition. I provide a party line ringing key Rh for connecting one of a plurality of ringin; generators G. G and (i to signal the subscriber at :1 called for common battery substation. A ringing control relay RC is also provided. which relay is enersized noon the actuation of the rinsing key RK to connect ringing current to the called lino and remains energized. until the called. subscriber answers in response to the. signal An interruptenrelay IR is p i'oyiddd which is energized upon the actuation of the fin es ey. K te c ee f 153 reht t'o; he elled lir 'eto give-an itista teneous first'rin to the called for-subsefifier. The relay R also connects the inter; I to the interrupter relay IR- to internif t enhy nergies .ea uslesp s re thes s)! LB tai termittently connect ringing current to t e called lin -To;s ,g al;a.l e ry bstafi m dheiope ato st d pr ss the: ringingcplungers; o c n ect curr t thecalledwline. each time the subsmfiion bell isv to :be "op ra d. LA ca l ng qp s ry lamp I .GL -is al oip r ded at)? t e s l S. pi IY SOF$'nP PQ$ $-n;.A lis ning key Lh pr ti ed t rronn c ingthe m ers. se 0 to. thecond ctq sto i quire t ew n s [the subscribers. .;I :also.;proyide an interl t1 fltj:- I,' forzflashing the supervisory signals nd l 4F1 6 disc nne tion is .glesir'ed, {is will'be more fiilly hereinafter, .de. scribed i Referrin now in general to l ggqz, ggsnow a-universa-fcord circuit-.0? also adapted gto coiinectr li nesmf diflerent' character,;1 1ch :as common battery andiloc ine co mon baittery, andzcotninon battery lines, or local, ,bat-

' terynnd local battery lines. To the leftof the drawing, I show a'commonbattery'substatifli AT and local.,batte t ysubstation B'-,

and to,-the;-right,of the drawing Ishow a common battery substation D' 'anda local batte'rryrsubs tationE'. Thecommombattery substations:A'- and D terminate respectively at-ithe exchange in line circuitsLfland ,L whiohjbotnprisethe usual IineIreLagS LR and;LR,;cut-o fi' relaysCO and C line signalsSj and S andrnultiple jacks J and J. The-local batter substations B and E terminate respective y at the exchange in line circuits L and U, which line circuits comprise the high resistance cut-oil relays CO and CO multiple jacks J 'andJ', and drop signalsDS and DS.

The cord circuit C comprises an answering plug AP and aicalling plug GP, the two plugs being connected by the heavily marked oonductors'and through the medium of a repeating coil RP comprising windings 1', 2, 3 and 4'. The answering end of the cord circuit C. comprises a switching relay SW, a supervisory relay SR and a disconnect relay DE. The calling end of the cord circuit'C' comprises a switching relay SW", a supervisory relay SR and a dis connect relay DR, the said relays operating in a similar manner to that described in connection with Fig. 1. Answering and calling supervisory lamps AL and CL are pro vided for'the usual supervisory purposes. The cord circuit C is also provided with manual ringing. and for this purpose I provide a ringing key RK which, when actuatcd connects ringing generator G to the tra'nsx'nits his discorinect signal. A' listening line nnhlnterrupter If also proirided for causin t e supervisory laixi'ps AL and CL when a local battery subscriber key'LK"is also pr'ovided'wliich, when actuated, eats the operators set 0 to the ctors to inquire the wants of a e as b cri r. l, a

avlng described in general the preferred arrangement of the circuits and apparatus employed in n'iy inventicn Twill now describe it more in detail operating in connection with the exchange systems as illustrated,

vpi tition of cofdcircuit of Fig. 1.

Referring noiv more paint-man to Fig. ihandts snmis c i e mmo e y s riber titub'st t .efin i t 5 1 h smes'e hsf t sewe t blig ifilh lfi fz essfiscu t t h Ifhe ,r y r hie reey spe t ener iti n, brings about the lighting of the line signal The apereteaectlnethe ed. i e i Mashe i Ing k y, L t cn e he on eiia torfs the -co rd co ndu ctors of jthe cord cjrcpit C and inserts the answering plug P into the jafck J of, the c nine line. A series energi zingcircuit is established for the cut-off relay oiithe ,line circuit L an -l swiehingr n SW df ,c d. i cuit it-kg saiicircuiti being traced from battery throu h thewinding of the switching relay syiover conductor 5, through sleeve contacts of the connected plug Al and jack and through theivinding of the cut-ofirelayco to ground. The cutoil relay C ,uponenerg zing, opens the circuit of the rela L R nhich relay restores and efiaces the line signal S. The closing of al terna te contacts 6 and 7 of the switching relay SW establishes an encrgizcing circuit for the supervisory relay SR traced from battery through the lower winding R of relay SR, conductor 9, alternate contac; T of relay SW. conductor .10, conductor l? winding of the repeating coil RP ring contacts oi the connected plug Al and jack J. through the now closed contacts of: the substation switch book, back over the tip contacts of the connected jaclrwl and plug AP. winding 1 of the repeating coil. RP, conductor 12. alternatecontact 6 of relay SW, and through the winding 13 of the supervisory relay 9R to ground. The opening of normal contai: 1% of thesupervisory relay SR prevents th premature lighting of the answering s'upm visorylnmp AL.

Common battery to common battery.

The operator now inquii-estlie wants of the calling subscriber at the common battery substation A. and assuming that it is the subscriber at the common battery substation B that is wanted the operator tests the mulgk yilil tacts24 and25 connectsdshe supervisory relayfilif to thepordconductors, but due to tiple jack of the called line in the usual manner, and assuming that the line is idle, she the calling plu CP into the jack Jf of the called line and this insertion of plug GP into jack J closes a series enermingcircuitfor the cut-ofl' relay C0. of t eline circuit L' and 'the-switching relay SW of the cord circuit C,'traced from battery through the winding-of the, switching relay Swfl, conductor,15,, sleeve contacts of the 'conneoted ,plug and jack- J, and through the winding of the cutoll relay CO to' g ound. ,The closing of alternate contacts 16 and 17- of the switching relay SW an energizi circuit for the calling superyisory lamp ISL, traced from battery- ,throughthe alternate contacts 17, condoctor T18; through the .lamp C -L, conductor n m RC, conductor. 21, alternate contactlo ofitlie relay SW, conductor :22 ,to. ground-at mea t? hs-irsalid u r .elrvisory lamp CL remaining lightedunt the operator actuates their-ingcleans otal et the open siwiteh hook contacts at the called substation Bathe said relaySR'. remains .at-

normaljnntil .the called subscriber answers.

The o erato'r next ,dc irst.

or s the ress es the proper lyepressedpositiomwhich moves en :springs 26 and 27 nects' therproper r' ing" enerator G, G, Gi or G tosignal callgd for subscriber at substation .B. Theclosing of alternate contact of the end springs establishes an energizing circuit for .the,ringing control relay RC, traced from ,battery through the winding of the said relay RC,-conductor 28, alternate contact 29 of relay SW, conductor -50, alternate contact 31 of relay SR, conductor 32, conductor 33, conductor 34, alternate contact 26 of the end springs, conductor 35 and conductor 22, to ground at normalcontact 23 of relay SR. .The relay RC,-'upon energizing, then closes a locking circuit for itself, traced from battery through the winding of relay RC, conductor 28, alternate contact 29 of relay SW, conductor 30, alternate contact 31 of relay SW, conductors 32 and 33, alternate contact 20 (If the ringing control relay RC, conductor 21, alternate contact 16 of relay SW, and conductor 22 to ground at normal contact 23 of relay SR.- The interrupter relay IR is also energized during the interval that the plunger of the ringing key RK is held down over a circuit traced from battery through the upper winding 36 of the relay IR, conductor 37, alternate contact 27 of the end springs, and conductor 38, to around at alternate contact 39 of relay HQ. The

contact 20 of the ,ringing control.

rl ie stfit st nging rR H of the ringing key.- toathelr alternate position,,and conhell of the called substation D, back through the ring contacts of the connected plug UP and jack J to ground at alternate contact *3 of relay IR. This connection of ringing current, immediately upon the depression of a ringing key plunger of ring key RH, gives an instantaneous first ring of the called subscribers call bell. The 0 ening of normal contact of relay 11C eliaces the calling. supervisory signal CL. The closing of alternate contact M of relay RC connects the" interrupter I to the lower winding 45 ol theinterrupter relay IR, the circuit being traced from battery throughthe winding 45 of the relay IR, alternate contact 44 of relay RC, conductor 46, through alternate contact 47 of relay SW, and through the constantly rotatin interrupter I to ground. The relay thus intermittently energized and deenergized to connect ringing current from the generator G to the called line over a circuit traced from the ungrounded pole of the generator G, through alternate contact 41 of the ringing key plunger contact, conductorfl2, alternate contact 40 oirelay IR, tip

tact 43 ,of rclay IR. The closing of nlternate contact 48 of relay Ill transmits an audible tone to the calling .'-n-J-.'-,'cribcr at the substation A, trnccri over a circuit extending from the nngroundeal pole oi" the generator G", ovcr conductor as). lhrrnng'h resistance :70, condenser 51, alternate contact 48 of relay 1H, conductor 52, tip conductor of the cord circuit C, winding 3 of the repeating coil RP, conductor in), alternate contact 24: of relay of relay Sit to ground The ringing tone is induced in the other windingof the repeating coil Iii and transmitted to the calling subscriber at substation giving the subscriber then-at nn au-lihle signal notifying circuit of the supervisory relay SP at the SW", through the upper Winding 1 Ill) - conductor 18 tobatte switch hook contacts. and the relay SR, upon rug-energizing, opens its alternate contact 31 to open the locking circuit of the ringing control relay RC. The relay RQ-upon deenergiziug, opens its alternate contact 44, disconnecting the interrupter I from the winding 45 of the relay I'R,'which relay decnergizes and opens its alternate contact 40,

thus preventing further application of ring iflg current. The-TelaySR restoring closes its normal contact 14, closing acircuit'for the answering supervisory lamp AL, traced from ground at normal contact l i, over con ductor 54 through alternate contact 5501 relay SW. through the lamp XL, and conduct/or 56 to battery and ground at alternate contact 51 of relay SW. The closing of normal contact 20 of relay RC, upon its restoration, closes a circuitiorthe calling supervisory lamp GL, traced"fro!i1 ground at normal contact 23 st relay SR'yconiductor :32, alternatehontactt' 16 of relay SW,"conductor 21-, normal contact Ell bi relay RC, conductor 19, through 'th'eflampx GL; and

I yahdgr%tid at alternate bontact"17 of'the' rela' 'S S The operator noting the-two lig tied'signals AL and CL knows that the calling subscriber has replaced his receiver and nowwithdraws the answering and calling plugs AP and GP from their respective jacks J and'J, open ing the series circuits-fer the 'relays CO and SW, and CO and SW. The relays SW and SW restoring, place the apparatus of the cord circuit C at normal; and the said cord is now available for establishing other connections.

The subscriber at the called substation l) in response to his call signal, removes his receiver from its switch hook, and when the relay IR is in one of its de-energized positions an ener izing circuit for the supervisory relay S is established, traced from battery through the lower winding 58 of re- 2 lay SR, over conductor 59, through alternate contact of relay SW. conductor 60, conductor 61, winding 4 of the re eating coil RP, normal contact 43 of relay I ring contacts of the connected plug CP and jack J. through the now closed contacts of the substation switch hook, back through the tip contacts of the connected jack J and plug CP, normal contact of relay IR, winding 3 of the repeating coil RP, condur-tor 53, alternate contact 24 of relay S V. and through the winding 62 of the supervisory relay SR to ground.

The opening of normal contact 22 of the supervisory relay SR opens the locking circuit of the ringing control relay RC. and the said relay RC restores, opening its al ternate contact 44, disconnecting the interrupter I from the winding 45 of the relay TR. which allows relay IR to remain at normal. The opening of alternate contact 40 of the relay IR prevents further application of ringing current from the generator G to the called subscriber who has now answered his callin response to his call signal. The calling and called subscribers at the substations A and D are now in conversational circuit, the talking circuit being traced over the heavily marked conductors.

Lifter the subscribers have finished conversation, they replace their receivers upon their respective switch hooks. causing the supervisor v relays SR and SR to restore. The restoration of thesupervisory "relay SR causes its normal contact 14 to close, establishing an energizing circuit for the answering supervisory lamp AL, traced from ground at normal contact 14, over conductor 54. through alternate cont-act of relay SW, through the lamp AL, and conductor 56-to battery and ound'atalternate (pntact 57 (if-relays The restoration-of the supervisory relay'SR' causes its normal contact 23 to close establishingan energizingcirctiit' for the calling supervisory lamp CL, traced from battery at alternate contact 17"o'f relay SW, o'ver conductor 18, through the lamp CL, conductor 19, normal contact20 of relay RC. conductor 21 alternate contact 16 of relay SVV', and conductor 22 to ground at normal contact 23 of relaySR. The operator noting the .two lighted signals knows theconversation has been terminated and withdraws the answeringand calling plugs AP andCP from their respective jacks J and J, allowing the switching relays SW and SW to restore, placing the apparatus of cord circuit C at normal ready for establishing other connections. The cut-off relays CO and CO also restore to normal when the plugs AP and (P are withdrawn. placing the line circuits L and L at normal.

Loco/Z battery to local battem Fig. 1.

Assuming now that the local battery substation E initiates a call, the actuation'of the hand generator by the subscriber brin about the operation of the drop signal D and the operator noting the actuated drop signal DS inserts the answering plug A1 of cord circuit C into the jack ll of the calling line. The insertion of the plug AP into the jack J restores the drop signal DS and establishes a series energizing circuit for the cut-oil relay CO and the switching relay SW of the cord circuit C. This circuit is traced from battery through the winding of" relay SlV, over conductor 5 through sleeve contacts of the connected plug A l and jack J and through the winding of the high resistance cutoff relay CO to ground. The cut-oil? relay CO energizes, but due to the high resistance of the said cut-oil relay (0 of the local battery line circuit T1 the switching relay SW fails to L and the switching relay SW of the cord v circuit C, traced from battery through the winding of the relay-SW; over conductor 15, through contacts of the connected plug CP -and jack J and through the winding of the relay CO toground: The switching relay SW does not operate, due to the high resistanceof relay Q0 and remains at normal, but the relay CO energizes. The operator now*ac'tuates one of the ringing key plunger-s o'fthe ringing key RK, and assuming that it is the generator G which is to be connected; the depression of the plunger to itsfully depressed position also actuates'the'end springs 26 and 27;

The closing of contact 26 of the end springs establishes an energizing circuit for the ringing control relay traced from battery through the windingof the relay RC, conduetor'28, norrrial contact 29 of relay SW, conductors 33 and '34, alternate contact 26, conductor 35, and conductor 22. to ground at normal'contact'23 of relay SR. The closing of alternate-contact 39 of relay RC- establishes an energizing circuit for the interrupter relay IR, traced from battery through the winding 36 of relay IR; conductor 37, alternate contact 27. and conductor 38, to ground at alternate contact 30. The closing of alternate contact 40 of relay IR connects ringing current from genereator G, through alternate contact 41 of the depressed key plunger of ringing key RK, conductor 42, alternate contact 40 of relay TR, tip contacts of the plug GP and jack .1, through the call bell of the called substationE back through the ring contacts of the jack J and plug GP. to ground at alternate contact 43 of relay IR. There is no locking circuit established for the relay RC. due to the switching relay SW remaining at normal, and for each application of ringing current the operator must depress the ringing key plunger. The locking circuit of the relay RC extends through alternate contacts of the switching rela SlV. and as the switching relay SVV' is at normal during the connection of the calling end of the cord cir cuit C to the local battery line E. the relay RC does not lock up. Relay Sil remain ng at normal also prevents the interrupter l from lPlllQ' connected with the illcrrupler relay IR. The operator thus rings the caL bell at the substation E until the called subscriber thereat answers. Assumin that the called subscriber at substation E? has answered, the conversational circuit may be traced over the heavily marked conductors. 7-

Assuming that the subscribers at the calling and called substations B and E have finished conversation, the subscribers'thereat restore their receivers upon their respective switch'hooks and actuate their hand generators to signal the operator of the'cord-c ircuit C. The subscriber at substation B having actuated his hand generator, currentwill pass through the disconnect relay DR of the cord circuit C over a circuit traced from the hand generator at the substation B, over the tip side of the line, through the tip contacts of the jack J 2 and plug AP winding 1 of the repeating coil RP, conductor 12, normal contact 6 of relay SW, conductor 63, through the winding of the disconnect relay DR, conductor '11, winding 2 of the repeating coil RP, ring contacts of the plug AP and jack J, and back to the generator at the substa tion B. When current passes through the disconnect relay, it is energized andcloses its alternate contact 64, bringing about the energization of the supervisory relay SR, over a circuit traced from battery through the winding 8 of the relaySR,conductor' 9, normal contact 7 of switching relay SW, conductor 65, resistance66, normal contact 67' of listening key LK, and conductor 68 to ground at alternate contact. 64*of the relay DR. The relay SR, upon energizing, closes 10K a locking circuit for itself, traced fromhattery through the winding 8 of the relay SR,

conductor 9. normal contact 7 of relay SW. conductor 65, resistance 66, normal contact 67 and conductor 68. to ground at alternate 10: contact 14 1f relay SR. When the subscriber at the calling substation B has ceased actuating his hand generator. relay DR- restorcs to normal, and closes a circuit for the answering supervisory lamp AL. traced from no ground at alternate contact 14 of relay SR. through normal contact- 64 of relay DR, over conductor 69, through normal contact 55 of rela SW, conductor 56, normal contact 57, con uctor 70, and through the constantly rotating interrupter I to battery and ground. The supervisory lamp AL is thus flashed, due to the interrupter I, giving the operator of the cord circuit C a dashing disconnect signal, or if the code signals have been arranged. the subscriber at the substa tion B may actuate his hand generator according to a predetermined code and notify the operator of the cord circuit C whether the flashing signal is either a disconnect signal or a recall Signal. During the actuation of the hand generator at the calling substation B the current passes through the relay DR and is thus held energized and its nor mal contact 64 remains open during this pcriod, preventing the interrupter circuit through the lamp AL from being. closed.

Thus the flashing'is started only after'the current from the hand genera-tor through the relay DR has ceas'ed. The operator noting the flashing: signal actuates her listening energizes and opens its alternate contact 14. interrupting the flashing circuit'o'f the lamp AL to prevent: further flashing'of thesignal.

The subscriber at the local batterysubstation E now actuates his hand generator'after finishing conversation, and the current from his hand generator a'ctuates the disconnect relay DR', as is apparent from the previous description in connection ='with relay DR. The closing of alternatecontact 71 ofthe (relay 'lDR establishes an energizing cirouit for the supervisory relay SR tracedoinom battery through the lower winding-- 5811f relay SR, conductor 59,. nornml contact 25 of relay SW", conductor I22 slstan'ce 73, normal contact-174v oflistening key LR, and conductor to ground at alternate contact 71 of relay DR'.- The relay SR now closes'a lockingcireuit for itself tracedfrom battery through Winding 58 of relay $R'; conductor -59, normal contact 25, conductor 72; resistance 73-; normal contact 74, and conductor '75 toground' at alternate contact '23 of relay SR. While the called'subscriberat'the local substation E is sending the (lisconnectsignal the call ing supervisory lamp is prevented from flashing for the reason previously described in connection with the supervisory lam AL. When the subscriber atthe substation A has finished sending a disronne'ct signal. the relay DR restores to normal, and the closing of normal contact 71 closes a circuit for the calling supervisory lamp (.L, l'rz-u'etl from ground at alternate contact 23 of relay SR, through normal contact 71 of relay DR, conductor 76, normal contact 77 of relay RC, conductor 78, normal contact 16 of relay Sll, conductor 21, normal contact 20 of rclay RC. conductor 19, through the lump CL. conductor 18, normal contact 17 of relav SW, conductor 79. a-nd through the interrupter I to battery and ground. The ca'll mg supervisory lamp (7L is caused to flash due to the constantly rotating interrupter I to give the operator a flashing disconnect signal, or in case of a code signal to signal the operator for a recall. The operator noting the two flashing disconnect signals of lamps AL and CL knows the conversation has terminated and now actu'ates her listen ing key LK to interrupt contacts 67 and 74 to open the locking circuits of relays SR and SR, allowing the relays to restore. The opening of alternate contacts 14 and 23 cl emon 1 4 relaysSR and SR opensthecircuit 05 the .fiashing supervisory signals AL and CL. .andl thus prevents flirt-her flashing of the signals. answering and calling 'plugs AP and UP The operator now Withdraws the from their respective jacks J and J, allowing the relays CO and C0 to restore. The apparatus of cord circuit'C and line'circuits, L and L are now at normal and available for establishing other connections.

When a local battery line' is signaled, the discharge of the line might bring up the relay DR and close a circuit for the relay SR, which would lockup and cause ihe signal -GL to' flash and'give a false disconnect it some means were'not provided-to guard against this. Fooyeicomethis, I [)I'( )V1(Il(3 a short circuit for the relay D'R, as will now "be described. After eachapplication of ringingcurrent, 'arCl'lSUllaIgBvfIOm the *line is sent back through" the tip of "the plug, through normal; contact 40, through Winding 3 of'the lepeatihg coil RP, over conductor 53, normal contact 2d of relay SVV', over conductor-80',- through alternate contact 8]. of r'elw BC,-which .relay b'e'in'g slow to release hol s up"'nhomentaril=y after each application of ringing current, over conductor 82. through normal contact 83 of relay IR, to the ring conductor ofthe cord circuit C. This path for the linedischarge placesa short circuit about the disconnect relay DR and prevents the line discharge from affecting the relay DE. The relay DR thus remains normal, thereby preventing the giving of a false disconnect signal;

('Ommon battery (0 local battery.

Should a calling common battery sub scriber at the substation A wish to converse with the local battery subscriber at he sub station E. the insertion of the plug Al into the jack .T brings about the energiimtion oi the switching relay SW and the cut-oil relay t). and the closing ol alternate contacts (3 and 7 of relay Sil brings about the actuation of the supervisory relay SR over llll line. The operator in inserting the calling plug l into the jack J oi the local but tery lino E brings about the cnergization of the relay (0 through the switching relay SVV', but the switching relay SW does not operate when connected to the local battery line for reasons as previously stated, The supervisory signal AL is brought into play as a disconnect signal when the calling com mon battery subscriber A hangs up. and tinflashing of calling supervisory lamp (L as a disconnect signal, when the local battery subscriber at substation E sends a disconnect signal, is readily apparent from the previous description.

Lora? hmfcry f common off ry.

The subscriber at the local battery sub lll ill

lit

'10 hue ie 9.. e mi eemee ingle? gbemgi iiem 'igggw '60 line, an vzi.'ssi.i1ziiiu r il; isidle, she inserts the plug into the jack J ofthe Wanted line. This lns'erlghn of plug G1 into the jack J closes a serieseircuit for the -relays C0 and SW. which relays operate asis an parent from the previous description. The

U ling supervisory lamp CL in this case remains lighbed nbil the called subscriber answers, the circuit hqing traced from but- 'tery s t alternate contact 91 of relay SW. through ,the lamp CL, alternate contact; of relay SW, to ground at normal contact 96of supervisory relay SR The operabor now ect/notes the ringm key 1 1K tweennect rin ggenerator Jr to the culledlinc to'ring e caII beII. of the called subscriber ,iit the substationDf; "The operator act hates .the Ikeyboconneetgenemtor G ior ea'ch application (if-ringing 011mm, and when the subscriber at substation D" answers, a reirctiit for the supervisory relay SRfffis closed over the Him, and the 'op'eningof norfpnfl .oontiicthiifi ofrelay SR eflacejs theqe'll- "ing' supervisory signal CL notifyingthe operator that the called-subscriber st sub- "stationI-D' nn'sweregi. The snhserihers its now in opnversefiihhal'eireuit; end the l nsesz t i'fi i'; m e ove the heavi ximtk d n t r Y. is l 1 ver'satmn has tei 'rninetech Hie irhs rihei int .fihe sobsigeti onsj kf findDf repleee 'their'n-eh :01ienmg'the. ClIClfiiPS ofthe supervisory L110;

ieys'fi fiiei sl SR3, e 'the elofingbf nbrmal' conacts '92 and 96 of relays SR a-n,d SR{ elosesaenei-lgizing circuits n15 the 'W m ii ca 2 9' iii w am fagnd The lagnps glowing! notify the ,operebor thet the 'eonyersation is fimshed. flohclishe nfowwithdrews falugs AP mam? Lirom theiriespeetive iaeks J and J jflfhe '100 .rel'nys SWf-imd SW' reslgoreQes do the eub. ofi' relays SO" and CO, and the app'zmitns w at, norm i vei eb i rT- eonnection'sff f Assuming nn vgthah the local bet-fiery suh- 'sc'riber alt snhstiition B initiates :1 (1111, the operation of the hmulgeneraitur thereof. 0 crates the drop signal DS at the (.ldllillgfl. and the npemt'nninserls the plug n" into the jack closing escri ws circuit for the high resistance cut-off relay (0" and lghc switching rchiy $12". The relay CO operates, but the relay SW? remains at; normal, as previously described in connection with Fig. 1. Assuming ii; is the subscrih r e% the local hatterr substation E that is'n'anted. the plug CP' is inserted into the jack J" of the wanted line. closing a series circuit for the switching relay SW and the high resist: :mce ,cut-oifrehiy CO. The relay (-O npcrates, hut. the switching relay S'W" does not, and remains at pmmni .glue 20 1 h highresists mre of relay C0. The operator aet iates tlie ringin key HR to connect ringing generator to the called line to operate the call signal at the called local. lmtterv substation E. and the signal is actuated until the subscriber thereat answers.

hen c'mversatif) hm l'cz'mirzite i. the calling and celled subscribers at substations new.W. tlu nti t* P198 Ye .B' angl E replace their receivers upon their DB? an 2. 1. M9, J .ci e i r us hessre r r l mps Ali-feed; L

through the intgrrnpter l 'Tlie'operatqr new the ,fiaag i. .iliseimec sme l o lamps AL' and L 'knoivsthat cqniiersa tien rela restore and plffi l 1 2.31 fii llllg of :ii have at: an su gesti- "ir in Pa o l Les a: Q ae i nes my invented-$ i or t mi djtp thss m s vis eusre. meantime. m st lbi mlifl. r. 1 ,9 9 sk l What I claim as new and desire secure by Unit tates Letters Patent 'is 4 1. -A telephone system including common battery and local batter telephone lines, a universal cord circuit or interconnecting said lines, a signal for said cord circuit, interrupter means for flashin said signal, a relay controlled over one 0. said local battery lines when the subscriber signals for disconnection for oonnectin said interrupter means in circuit with sai signal thereby opening and closin the circuit of said signal causing the same 0 flash, and a relayfor said signal to low continuously when a common battery line signals for disconnection.

2. A tele hone system including common battery an local battery telephone lines, a universal cord circuit for interconnecting said lines, a supervisory signal for said cord circuit, interrupter means for flash g said supervisory signal, a ,relay control ed over one of said local battery lines when the subscriber si als for disconnection for associating said interrupter means with said signal to flash the same, said interrupter means being ineffective to flash said signal as long as teen said relay is energized, and means. for cans m said signal to' g'l'ori continiiousl wh at common bat'tery hne signals for" connection.

3. A telephone system including a local battery telephone 11116;, and ac'onunon battery telephone line, a link circuit for connection to said lines, a signal for said circuit, an interru ter device, means controlled over said local attery tele hone line then the subscriber signals for islcdnnection ibr connecting said interrupter vderi e in circuit with said signal thereinopening andclosiiig the circuit of the same to cause the signal to be intermittent operated, means o'o ritrolled cver said common battery liiie jyvlieh the said link circuit is 'c n ect difb gnfigl commonbattery line for causing spid's'igngil to glow continuously whenidisconnwtioii' is signnlled for. i

e. A telephone steminclug l i n'g a local 8 t ry e eph n n mmon. b tery line," a link a circuit fie;- connection 'Isagrl lines,a signal for'said ljnlr'cii'ciiit, interrupter device, means controlle'cl 'over di'd er sig l r d swnfle is plating said interrupter device sausage-si nal for fiashin the some; said Ineaiisdiein'g ineffective to aa'shsaid'signal during the period. aid subscriber is operatig his eg-' note, and means for cousin" to glow continuously when 'a li c ii'cui nected to said common battery line, said common battery subscriber si nals or the 00 connection.

5. A telephonesystem including local battery and common battery telephone lines,' a universal cord circuit fon'interwnnecing said lines, a signal for said cordffcincnit, means controlled over one of common battery lines for causing said snpery'isiiiffv signal to glow continuously, means. "controlled over one of: said local batteriz lines local battery line to connect said interrupter means in circuit with said signal to open and close the circuit thereof, thereby causing the si al to flash. V

7 A. telephone system including lo calb ettery and common battery telephonedines, a universal cord circuit or connecting lines, a signal for said cord circuit, means controlled over a common battery line to cause said signal to glow continuously, ini- 13D terrupter means, means controlled over a local battery line to connect said interrupter means in circuit with said signal to open and closet-he circuit thereof thereby causing the signal to' glow intermittently, and operator controlled means for disassociating said interruplter means from said signal.

8. A telep one s stem including local battery and common attery telephone lines, a universal cord circuit for interconnecting said lines, a signal for said cord circuit, interrupter means, a relay for said cord circuit controllable over one of said common battery lines for causing said si al to glow continuously, and a relay for sai cord circuit controllable over one of said local battery lines for connecting said interrupter means in circuit-to open and close the circuit of said signal thereb causing the same to flash.

9. A telep one system including a local battery subscribers telephone line, a. common battery subscribers line, a link circuit.

forconnection to 'saidzlines, a supervisory si nal, interrupter means, a relay controllaile over said local battery subscribers telephone line when said subscriber is si aling for disconnection for connecting saig interrupter means in circuit with said supervisory signal to open and close the circuit thereof to cause the same to be flashed intermittently, and means for causing said si al to glow continuously when a link circuit is connected to said common battery subscribers line and the subscriber signals for disconnection.

10. A telephone system including a local battery subscribers telephone line, a common battery subscribers line, a link circuit for connection to said lines, a supervisory signal, interrupter means, a rela control lable over said local battery subscribers telephone line when said subscriber is signaling for disconnection for connecting said interrupter means in circuit with said supervisory signal to open and close the circuit thereof to cause the same to be flashed intermittently, operator controlled means fordisconnecting said interrupter means from said supervisory signal, and a relay controlled over the common battery subscribers line when the link circuit is connected to a common battery subscriber for causing said sig nal to glow continuously when the common battery subscriber signals for disconnection.

11. A telephone system including local battery and common battery telephone lines, a universal cord circuit for interconnecting said lines, an answering and a calling supervisory signal for said cord circuit, means controlled over said common battery lines for causing a continuous glow of said signals when disconnection is signaled for, and means controlled over said local battery lines for causing intermittent operation of said signals by the opening and closing of the circuit thereof when disconnection is signaled for. said last means including a source of current and an interrupter located at the exchange.

12. A telephone system including common battery and local battery telephone lines, a universal cord circuit for interconnecting said lines, a signal for said cord circuit. means controlled by one of said common battery subscribers for causing a continuous glow of said signal. an interrupter. and a relay controlled by one of said local battery subscribers for connecting said interrupter in circuit with said signal to open and close the circuit of said signal, thereby intermittently operating the same.

13. A telephone system including common battery and local battery telephone lines, a universal cord circuit for interconnecting said lines, a signal for said cord circuit, means controlled by one of said common battery subscribers for causing a continuous glow of said signal, an interrupter, a relay controlled by one of said local battery subscribers for connecting said interrupter in circuit with said signal to open and close the circuit of said signal to cause the same to flash, and operator-controlled means for disassociating said interrupter from said signal.

14. A telephone system including local battery and common battery subscribers telephone lines, a universal cord circuit for interconnecting said lines, a signal for said cord circuit, a relay for said cord circuit, an interrupter. means controlled over one of said common battery lines for causing the de-energization of said relay to effect a continuous glow of said signal, and means controlled over a local battery line. for causing an encrgizat-ion of said relay to connect said interrupter in circuit with said signal to cause an intermittent operation of the same.

15. A. telephone system including local battery and common battery subscribers telephone. lines. a universal cord circuit for interconnecting said lines, a signal for said cord circuit. a relay 2" or said cord circuit, an interrupter, means controlled over one of said common battery lines for causing the de-energizatimi of. said relay to effect a continuous glow of said signal, means controlled over a local luittery line for causing an energization of said relay to connect said interrupter in s'll'flllb with said signal to cause an intermittent operati n: of the same, and operator-coutz-olled, means for disassociating said interrupter from said signal.

16. A telephone system including local battery and common battery telephone lines, a universal cord circuit for interconnecting said lines. a supervisory signal for said circuit, a supervisory relay. a switching relay,

means operable when said cord circuitis eon nected to a common battery one of said lines to operate both of said relays subscribercontrblled-means for tie-energizing said supervisory relay, thereby causing a oontinnous operation of said supervisory signal, and means controlled over a local battery one of said lines for energizingsaid supervisory relay, thereby connectin said interrupterin circuitwith said signal to cause an intermittent operation of the same.

17- A telephone system including local battery and common battery telephone lines, a link circuit for interconnecting said lines, a supervisory signal, a supervisory relay, and a switching relay for said link'circuit, said relays being operable when tlielink circuit, is connected to one of saidcommon battery lines bojea'use acontinuous low of saidisignalwhen disconnection is signaled fog-and o rallleiwhen connected toone'of said local then-y lines to connect an inter rupten in thecircuitrof said signal-when ronnection is signaled for to cause an intermittent operation of said signal.

l-EA telephone syseem including magneto and common bat-tel telephone lines terminating at a cent-mi ofiice, a link circuit for interconnecting said lines, a signalfor said link circuit, a pair of relays for said link circuit, means for energizing said relays and then (le'energizin one of said relays when a common battery linc is connected with, to cause a continuous operation of said-signal to denote (,lifiCOUl'lBCliOIL and means for energizing one of said relays while permitting the other relay to remain at normal'when a local battery line is connected with, to connect an interrupterin'cirunit with said Eignal'to cause an intermib tent operation thereof when disconnection is signaled-for. I

Signed by me at Chicago, in-tlie-eount'y of Cook and State of 0f July,1918. H 3H ARLES "SPARKS.

Illinois, this 31st day- 

